The present invention relates to a fuel supply control system for controlling the amount of fuel supplied to an internal combustion engine, and more particularly to a fuel supply control system in which a fuel supply control means is driven by a step motor.
Fuel supply control means such as throttle valves in spark ignition engines and control levers in diesel engines have conventionally been driven by a step motor which is energized to a step position corresponding to a position to which an accelerator pedal is depressed for thereby effecting fuel supply control.
When the starter motor is energized to start the internal comubustion engine, the voltage of a main power supply is lowered, therey casusing the voltage applied to an excitation circuit of the step motor to drop. This is disadvantageous in that the step motor cannot be rotated to a step position commensurate with a position to which the accelerator pedal is depressed when the engine is started.